Tissue processors can be operated with varying levels of automation to process human or animal tissue specimens for histology or pathology uses. Various types of chemical reagents can be used at various stages of tissue processing and various systems have been developed for delivering reagents to specimen containing slides. Examples of known reagent delivery systems include small quantity release dispensers, manual pouring into reagent vats, or via bulk containers connected with a processor via tubing.
There are various disadvantages of known systems. For example, manually pouring into, or draining, reagent vats is time consuming and requires pouring accuracy, thereby decreasing the overall efficiency of the tissue processing system. Another disadvantage is that manually pouring and draining reagents can be sloppy, requiring clean-up of spills and consequential instrument down-time. A further disadvantage is that selecting the correct reagent requires operator attention and accuracy and there is an increased possibility of reagent application errors, resulting in a decrease in test accuracy and operational efficiency.
Automated systems also present various disadvantages. Reagents need to be selected and administered to slides during processing. The reagents frequently need to be delivered via gravity promoted dispensing from above. Such delivery systems require specialized equipment for reagent delivery such as specialized reagent dispensers or drivers or automated pipetting systems. Such systems suffer various drawbacks such as the amount of effort required to set up and dispense the reagents, the possibilities of evaporation during processing or contamination and difficulties in handling minute quantities of large numbers of reagents.
One known slide retaining tray and system for staining tissues is described in U.S. Pat. No. 5,338,358, which is incorporated herein by reference. As illustrated in that patent, a platen is provided and various mounting elements are provided to mount a slide on the slide tray. Space for five slides is illustrated. A reaction chamber is provided between a platen surface and a slide mounted on the tray. Reagents are introduced into the reaction chamber via drip surfaces and attendant capillary action. Additional known slide retaining trays and systems are described in U.S. Pat. Nos. 5,695,942 and 5,965,545, which are incorporated herein by reference. As illustrated in those patents, individually heated or cooled slide retaining apparatus are provided. The slides are positioned adjacent a surface and reagents can be introduced between the slides and their respective surfaces, such as by melting a gel containing a reagent by heating.